Inscovery - Discover unique Instagram users that share your interests
hashtags.org - Hashtag is an extensive hashtag research platform for analytics and tracking of hashtags, providing...
Roundio - Explore what people posted to Instagram or Flickr near you
HashtagWiki.com - Hashtag Generator Tool
Instaround - A simple app to find Instagram photos and people around you.
RiteBoost - Auto-hashtags, Auto-emojis, GIFs and much, much more, all according to your Enahce rules.